Lubricating oil



Patented Sept. 11, 1945 LUBRICATING OIL Charles M. Blair, Jr., WebsterGroves, Mo., assignor to Petrolite Corporation, Ltd., Wilmington, Del.,a corporation of Delaware No Drawing. Original application Marci, 1943,

Serial No. 489,237. Divided and this application February 21, 1944,Serial No. 523,349

7 Claims.

This application is a division of my pending application Serial No.489,237, filed May 31, 1943, and relates to an improved lubricating oil.

In my parent application for patent above referred to I have disclosed anew type of polyester products 01. high molecular weight, consisting ofpolyesters of a resinous or semi-resinous character, that can beproduced or prepared by esterilying an alpha-beta unsaturated acid oranhydride with an unsaturated aliphatic alcohol, of.a particular kindtherein described. under conditions which result in polymerization oftheester.

My present, invention consists of a new composition, composed of orcomprising a relatively small amount of a condensation polymer of thekind described in my parent application above referred to, and alubricating oil.

The preparation of resinous and semi-resinous products by reaction ofmultifunctional acids with multi-functional alcohols is, of course, anold and well known art. More recently polyesters of high molecularweighthave been prepared by polymerizing ethyl or methyl esters offumaric and maleic acids. Still more recently, resinous products havebeen prepared by polymerizing esters of polybasic acids in which atleast one or the carboxyl groups is esterified with a low molecularweight, unsaturated alcohol, such as allyl alcohol, methallyl alcohol,crotyl alcohol, methyl vinyl carbinol, or other highly reactiveunsaturated alcohol of the allyl type.

The reactions leading to resinification of esters of the low molecularweight unsaturated alcohols mentioned above apparently depend upon theextreme reactivity of the unsaturated alcohols and the tendency forthese to condense with themselves or with one another under relativelymild conditions. Esterification of these alcohols does not completelyinhibit their ability to condense. Alcohols which have been described assuitable for preparingsuch resins, are those of the allyl type, and allare characterized by the fact that the carbon atom attached to thehydroxyl group is in turn attached to an ethylenic carbon atom.

I have found that very unusual and usefulpolymeric substances may beprepared from unsaturated carboxylic acids and certain unsaturatedalcohols, which may not-be multireactive in the sense that the acidshave two or more carboxyl groups and the alcohols two or more hydroxylgroups; More specifically, the polymeric compositions of the presentinvention are those obtained by reacting alpha. beta unsaturated acidsor anhydrides with unsaturated aliphatic or cycloaliph'atic alcohols, inwhich the ethylenic carbon atom nearest to the carbon atom attached tothe hydroxyl group is separated from said hydroxyl' attached carbon byat least three singly bonded carbon atoms.

Acidic reactants found suitable for use in the preparation of the abovementioned polymeric substances, are the alpha beta unsaturated acids andanhydrides, preferably those containing less than 10 carbon atoms.Examples of such acids and anhydrides are crotonic acid, maleic acid,fumaric acid, citraconic acid, glutaconic acid,

.aconitic acid, itaconic acid, mesaconic acid,

maleic anhydride, citraconic anhydride, itaconic anhydride, and thelike. Suitable acidic reactants may be monobasic, dibasic, or polybasic.Because of their relatively low cost and availability in commercialquantities, maleic anhydride, fumaric acid, and citraconic anhydride areespecially useful; and products obtained with these reactants will beused below to illustrate the present invention.

Suitable alcohols for use in preparing the polymeric substances are thealiphatic and cycloaliphatic unsaturated alcohols, in which theethylenic carbon atom nearest tothe hydroxyl group is separated from thecarbon atom attached to said hydroxyl group by at least three singlybonded carbon atoms. Such alcohols may be monohydric, dihydric, orpolyhydrlc; they may be primary, secondary, or tertiary; and theycontain one or more carbon-to-carbon double bonds. My preferred class ofalcoh'ols are the primary and secondary monohydric, aliphatic, andcycloaliphatic unsaturated alcohols which contain 8 or more carbonatoms, and contain less than 32 carbon atoms, and which satisfy theabove stated requirement for position or the double bond with respect tothe hydroxyl group. Examples of preferred alcohols are: Octene-3-ol-8,decene-l-ol- 10, oleyl alcohol, erucyl alcohol, linoleyl alcoh'ol,eicosene-lO-ol-l, citronellol, rhodinol, abietyl alcohol, dihydroabietylalcohol, crude sperm oil alcohols, crude Jojoba oil alcohols, and thelike.

,The most desirable type or alcohol contains at simply by heating thereactants at the proper temperature, for a period of several hours.

To obtain the highest degree of polymerization in the shortest period oftime, I have found that certain conditions of reaction are particularlydesirable. The determination of these reaction conditions actuallyconstitutes an invention within an invention, in that it makes possiblethe preparation of the most desirable polymeric products with theminimum of time and eflort. In particular, I have found that thepolymerization is promoted bypassing through the mixture, duringreaction, a. slow stream of oxygen or oxygen-containing gas, such asair. The beneficial'eitect of this operation appears to arise directlyfrom the oxygen in the gas used. If nitrogen, hydrogen or other inertoxygen-free gases are passed through the mixture, the rate ofpolymerization is not appreciably increased. The use of benzoylperoxide, also, does not catalyze the polymerization to an extentcomparable to that obtained with oxygen gas. In fact, extensive effortsto find a comparable catalyst have so far failed.

when using oxygen or oxygen-containing gas as a catalyst, thetemperature of the reaction may vary over rather wide limits; but I haveobtained best results within the range of 110 C. to 215' C. withreactants that boil within this temperature range, it is desirable toreact the materials under pressure, or to conduct the reaction for awhile at a lower temperature until esteriflcation f the reactants hasproduced an intermediate of higher boiling point. The temperature maythen be gradually increased to a higher value. At extremely hightemperatures, decomposition and oxidation of the product may occur to anobjectionable degree.

The following examples will serve to illustrate the methods ofpreparation which may be employed. Parts are by weight.

Example 1 135 parts of commercial oleyl alcohol (iodine No. 71.0) and 50parts of maleic anhydride were heated and stirred in a flask fitted withan air condenser. The temperature was raised, over a period of twohours, to 240 C., and was held at this point for 12 hours.

The product was a light red, soft wax at room temperature. It had aniodine number of 46.5, a neutralization equivalent of 1090, and amolecular weight (cryoscopic in benzene) of 3290. The product wasclearly soluble in lubricating oil.

Example 2 135 parts of commercial oleyl alcohol (iodine No. 71.0) and 50parts of maleic anhydride were heated and stirred in the apparatus ofExample 1. After raising the temperature over a onehour period to 160C., a gas inlet tube was introduced into the flask and a slow stream ofair was allowed to bubble through the liquid. The temperature was heldat 160 for 18 hours, while allowing air to bubble through the flaskcontents.

The product was a reddish, viscous oil at room temperature. It wasclearly soluble in an SAE 20 lubricating oil in all proportions. Dilutesolutions in lubricating oil greatly increased the viscosity index orsame.

Example 3 The reactants of Example 2 were held for 27 hours at C. whilepassing through a slow stream of air.

The product was a stiff rubbery mass. It was partially soluble inlubricating oils. giving very viscous solutions.

Example 4 157 parts of crude jojoba oil alcohols (mainly eicosenyl anddocosenyl alcohols) was substituted for the commercial oleyl alcohol ofExample2.

The product was similar in properties to that of Example 2.

' Example 5 59 parts of fumaric acid was substituted for the maleicanhydride of Example 2. A water trap under a water-cooled condenserserved to catch evolved water.

The product was almost identical in properties to that of Example 2.

Example 6 Example 7 Linoleyl alcohol was substituted for the oleyialcohol in Example 2.

It will be noted that some of the above products, for example, those ofExamples 1, 2, 3,4, 5 and 7, are prepared from one molal proportion of adibasic acid and one molal proportion of a monohydric alcohol. Suchproducts contain some free carboxyl groups. Analysis of the product ofExample 1 indicates that somewhat less than the theoretical number ofcarboxylic acid groups remains. It is believed that this result mayarise from some decarboxylation at the temperature of reaction, i. e.,240 C.

Products containing free carboxylic acid groups may be reacted withalkalies, amines, heavy metal oxides, etc., to yield polymeric saltswhich have useful properties in addition to those of the polymers alone.Salts, such as the sodium salt of the product of Example 2, may be usedas sludge dispersers or detergents in lubricating oil. The lead salt ofthe product of Example 2 may alsofltge used as a thickening. agent anddetergent In general, products of the present invention which containfree carboxyl groups may be em- The nature of the reaction whichresultsin the formation of the present products is not clearly understood, butit is believed that the droxyl. group of the alcohol. and also condensesby proton transfer, with the unsaturated alcohol at anethyle'nic carbonatom of same, or at a carbon atom" near the double bond. The unsaturatedalcohol undergoing condensation with a molecule of ethylenic acid isprobably est'erifled by a diilerent molecule of ethylenic acid; so-atype of linear polyester is formed. when the double bond of theunsaturated alcohol is nearer to the hydroxyl group than allowed by theconditions previously given. good yields of the desired products arenotobtained. It is believed that this is the result of the formation ofstable, cyclic, inner esters. rather than linear-polyesters. Variouspossible reactions which are believed might occur in the preparation ofthe present compounds, are as follows, employing an unsaturatedaliphatic alcoholand an alpha beta, ethylenic, monocarboxy, aliphaticacid: aR.CHiCH=CH-OH,OH:.B'.QHiOH+nR".CB=CH.OOOK

The following are examples of my new composition:

Example I by weight of the product of Example 2, above, was added to alubricating oil having a viscosity index of '10, and a viscosity at 210F. of 46 seconds. Theresulting clear oil solution had a viscosity indexof 127 and a viscosity'of 5.8 seconds at 210 1". Y

Example I! 2% by weight of the product of Example 5, above, was added toa lubricating oil having a viscosity index of and a viscosity at 210 F.of 44.9 seconds. The resulting oil had a viscosity index of 85.0 and aviscosity at 210 F. of 47.2 seconds.

Greater or lesser eilects on viscosity index than those illustratedabove may be obtained by adding more or less reagent. "Using a productof higher intrinsic viscosity, such as that of Example 3, less reagentis required for a desired improvement in viscosity index. In general,the percentages of such products which will be employed varies from aslittle as 0.25% to as much as 5%, or even more, depending upon the useto which the oil is to be put. Thus, one object of my invention is thepreparation of such improved lubricating oils or, lubricating oilcomposition by adding not less than about 0.25%, or'more thanabout 5% ofthe herein described compounds to lubricating oils, such as are used ininternal combustion engines;

The present products are, in general, unsaturated, as reaction does notremove all of the In the above formulae, R and R" represent alkyl groupswhich contain one or more carbon atoms, and R is analkylene group whichmay contain one or more carbon atoms. 11. is a whole number. Where theethylenic acid is dior-polybasic, reactions similar to the above mayalso occrn.

In addition to the above reactions, several others are conceivablypossible. However, it is understood that the exact reactions are amatter of speculation or conjecture, and may vary, depending, in part,on the particular reactants selected. Such reactionsare not to beconstrued as a limitation in any respect, but are submitted in ordertoshow the diverse nature of the possible or probable reactionsinvolved,and additionally, to indicate the inability adequately to portray-theinvention in terms of conventional chemical formulae.

My present invention consists in using productsof 'the kind previouslydescribed, to increase the'viscosity, and viscosity index of lubricatingoils, or consists. of a new composition of matter composed of arelatively small amount of such a condensation polymer and a lubricatingoil.

Compounds of the type herein contemplated are referred to ascondensation polymers. This is in conformity with nomenclature inOrganic appended claims reference to an aliphatic alcohol is intended toinclude the cycle-aliphatic alcohols. Reference to a straight chainalcohol must, of course, contemplate only the acyclic type.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A lubricating oil, consisting oi a mineral lubricating oil and.a,relatively small amount of an ester; the amount of said ester beingwithin the approximate range of 0.25% to 5% by weight,

based on the weight of the aforementioned mineral lubricating oil, andsaid ester being an alphabeta unsaturated carboxylic acid-unsaturatedaliphatic alcohol polyester addition-condensation polymer; said acidcontaining less than 10 carbon atoms and being free from vinyl radicalsand said alcohol containing at least 8 and less than 32 carbon atoms,and having at least 3 intervening carbon atoms between the carbon atomsto which the hydroxyl group is attached and the nearest ethylenic carbonatom.

2. A lubricating oil, consisting of a mineral lubricating oil and a.relativeLv small amount of an ester; the amount of said ester beingwithin the approximate range of 0.25% to 5%, by weight, based on theweight 01' the aforementioned mineral lubricating oil, and said esterbeing an alphabeta unsaturated carboxylic acid-unsaturated straightchain aliphatic alcohol polyester addition-condensation polymer; saidacid containing less than carbon atoms and being free from vinylradicals and said.- alcohol containing at least 8 and less than 32carbon atoms, and having at least 3 intervening carbon atoms between thecarbon atom to which the hydroxyl group is attached and the nearestethylenic carbon atom.

3. A lubricating oil, consisting of a. mineral lubricating oil and arelatively small amount of an ester; the amount of said ester beingwithin the approximate range of 0.25% to 5%. by weight, based on theweight of the aforementioned mineral lubricating oil, and said esterbeing an alphabeta monoethylenic carboxylic acid-unsaturated straightchain aliphatic alcohol polyester addition-condensation polymer; saidacid containing less than 10 carbon atoms and being free from vinylradicals and said alcohol containing at least 18 and not over 22 carbonatoms, and having at least 3 intervening carbon atoms between the carbonatom to which the hydroxyl group is attached and the nearest ethyleniccarbon atom.

4. .A lubricating oil, consisting of a mineral Y lubricating oil and arelatively small amount of an ester; the amount of said.- ester beingwithin the approximate range of 0.25% to 5%, by weight, based on theweight of the aforementioned mineral lubricating oil, and saidesterbeing an alphabeta monoethylenic dicarboxylic acid-unsaturated straightchain aliphatic alcohol polyester addition-condensation polymer; saidacid containing less than 10 carbon atoms and being free from vinylradicals and said alcohol containing at least 18 and not over 22 carbonatoms, and having at least 3 intervening car-bon atoms between thecarbon atom to which the hydroxyl group is attached and the nearestethylenic carbon atom.

5. A lubricating oil, consisting of a mineral lubricating oil and arelatively small amount of an ester; the amount of said ester beingwithin the approximate range of 0.25% to 5%, by weight, based on theweight of the aforementioned mineral lubricating oil and said esterbeing a maleic acid-monoethylenic straight chain aliphatic alcoholpolyester addition-condensation polymer; said alcohol containing atleast 18 and not over 22 carbon atoms, and having at least 3 interveningcarbon atoms between the carbon atom to which the hydroxyl group isattached and the nearer ethylenic carbon atom.

6. A lubricating oil, consisting of a mineral lubricating oil and arelatively small amount 0! an ester; the amount of said ester beingwithin the approximate range of 0.25% to 5%, by weight, based on theweight of the aforementioned mineral lubricating oil and said esterbeing a iumaric acid-monoethylenic straight chain aliphatic alcoholpolyester addition-condensation polymer; said alcohol containing atleast 18 and not over 22 carbon atoms, and having at least 3 interveningcarbon atoms between the carbon atom to which the hydroxyl group isattached andthe nearer ethylenic carbon atom.

7. A lubricating oil, consisting of a mineral lubricating oil and arelatively small amount of an ester; the amount of said ester beingwithin the approximate range of 0.25% to 5%, by weight, based on theweight of the aforementioned mineral lubricating oil and said esterbeing a citraconic acid monoethylenic straight chain aliphatic alcoholpolyester addition-condensation polymer; said alcohol containing atleast 18 and not over 22 carbon atoms, and having at least 3 interveningcarbon atoms betweenthe carbon atom to which the hydroxyl group isattached and the nearer ethylenic carbon atom.

, CHARLES M. BLAIR, Jr.

